1. Domain class diagram.
Produce an analysis class diagram focusing on the problem domain. At this point it is
not required to be fully attributed. However it is important that you attempt to model as
many of the entities as possible, and to ensure the correct multiplicity. A large amount
of the required information is present in the OVERVIEW section of the case. However it
is important to study the whole case as there may be other details or important context
that is situated in other sections. (35)
2. Decision Table.
Draw a decision table to capture the logic of determining the priority category for a call.
This is explained in the interview section on page 6.
You may wish to follow the decision table examples/exercises used in the tutorials as a
template and starting point for this exercise. (25)
3. Activity Diagram.
Draw an activity diagram to show the flow of activity for the process of logging an
emergency call and dispatching a response team. Most of this activity flow is explained
in the interview section of the case on page 8. Two of the most relevant items have
been highlighted in the case as a hint but other useful information may be present
elsewhere. End the activity diagram with Close Emergency Call even though this may
not explicitly be stated in the interview section highlighted. (20)
4. Activity Diagram.
Draw an activity diagram to show the flow of activity for the process of supervisor actions
on waiting emergencies. This describes the situation when an operator is attempting to
dispatch a response team but no teams are available. As with previous questions, the
most relevant section of the case has been highlighted as a hint. (20)
The following sections provide an overview of Rescue911, providing background to the
business, problems experienced, and requirements for the new system. Additional
detailed information is presented in the form of data gathered from interviews with key
Rescue911 is an ambulance and emergency services company. The company operates a
single 24- houremergency operations call center in which all calls to Rescue911 are received
and processed. Response teams are dispatched by call center operators. They are all trained
emergency medical dispatchers. Rescue911 has approximately 2000 EMTs (emergency
medical technicians) working in these response teams. Response teams are located at 25
base stations that are distributed across the geographic region serviced by Rescue911. As a
private ambulance and emergency services company, the assignment of response priorities
and the coordination of the dispatch process are core to Rescue911s value offering. The
dispatcher plays a key role in matching Rescue911s response capability to emergency
situations.Rescue911 knows that the overall effectiveness of the EMS system begins with the
logging of emergency calls and the dispatch of response teams.
People that make use of Rescue911s services include subscribers and non-subscribers. Direct
subscribers are individuals or families that subscribe directly to Rescue911and pay a monthly
fee. Indirect subscribers are automatically subscribed to the services of Rescue911 as a result
of their medical aid scheme, home insurance or life assurance policies. These medical aid and
insurance companies are called providers. The indirect subscribers do not pay the monthly
fees; instead Rescue911 recovers monies from their providers by billing the providers directly
for the services rendered. Non-subscribers can also make use of Rescue911s services i.e.
Rescue911 will respond to all emergency calls received. However, non-subscribers will be
billed for any emergency care provided to them.Rescue911 has seen significant growth in
operations in recent years. They currently have 2 million subscribed members (direct and
indirect), 2008 revenue was $500million, and in the first 6 months of 2009 they have
responded to 125 000 emergency incidents, an average of 25 emergencies per base station
Rescue911 has a flat organizational structure. Beyond the Chief Executive Officer (CEO) there
are only three senior managers, the Chief Medical Officer, Chief Operating Officer and the Chief
Financial Officer. The responsibility of the Chief Medical Officer is to make sure that
Rescue911s dispatching and medical procedures adhere to the expectations of the National
Association of EMS Physicians. The Chief Operating Officer is responsible for the day to day
business. He is in charge of the call center and all base
stations. The call centers operators are emergency medical dispatchers certified by both
national and international academies of emergency dispatching and have been trained in
emergency telecommunications. Rescue911s organizational structure is depicted in Figure 1.
Figure 1 Organizational Structure
The recent growth of Rescue911 has not come without its problems. Rescue911 has begun to
receive numerous complaints about their services from subscribers and providers. They are
also under increasing pressure from the government, hospitals, doctors, medical aids and
insurance companies to properly account for their services. Typical problems include: spending
too much time monitoring and coordinating response teams instead of focusing on the medical
aspects of dispatching, lack of real-time information on EMT and response team availability,
inability to confirm for callers whether a response to an emergency has been dispatched or to
provide details on the response configuration, inability to determine which emergency calls
have been closed / concluded and which are still in progress, under qualified teams are often
dispatched and themes arriving at a scene are not adequately skilled to deal with the
emergency situation, over qualified teams are being dispatched to noncritical incidents leading
to poor utilization of skilled resources, lack of proper documentation of services provided at a
scene to both subscribers and non-subscribers, inaccurate records of shifts worked by EMTs
at the various base stations, incomplete records of EMTs and their qualifications, and lack of
metrics for performance management especially in relation to response turnaround times.
Rescue911 management has determined that many of the problems result from inadequate
systems that have not kept pace with their growth rate. They aim to solve these problems
through the introduction of a new information system. The system is to be called ERIS
(emergency response information system).
The new ERIS system is aligned to Rescue911s objective to maintain the infrastructural
capacity needed to deliver comprehensive emergency service solutions. Through the
implementation of ERIS, Rescue911management aim to ensure the company can realize its
key performance objective to standardize the process of call logging, ensure accuracy of
response team dispatching, and improve pre- hospital treatment and customer satisfaction with
response performance. The system will also provide for improved internal operational
effectiveness, more efficient utilization of response teams, and better management control over
There will be three groups of users of ERIS:
1. Call Center Operators, the emergency medical dispatchers, who will use ERIS to log
emergency call details, dispatch one or more response teams, and follow up on calls
dispatched. Supervisors are a type of operator who are also able to deal with those
emergency calls to which operators are unable to dispatch a response due to response team
unavailability, and to authorize the cancellation of an emergency response
2. EMTs that will report for duty (clock-in) at the beginning of their shift by logging into ERIS and
will also use ERIS to input details about patient care provided at emergency scenes
3. Rescue911 managers who will use ERIS to produce certain reports. These reports included
demand reports, schedule reports as well as exception reports. Managers are also
responsible for maintenance of master file data.
ERIS will be implemented using a phased approach. Based on the needs identified, the
following requirements have been defined for inclusion in the first-phase of the ERIS project
(see Table 1), while later phases will incorporate billing, accounting and finance, vehicle and
asset management, and a mobile, PDA based, EMT-patient caresub-system.The above
requirements will be met through the following four sub-systems:
1. Computer aided dispatch sub-system (CAD) Primary users: Operators and Supervisors.
Log emergency calls received.
Dispatch, track and manage emergency responses.
1.c.Reporting and online querying.
2. Base Station management sub-system (BSMS) Primary users: EMTs and Managers.
Base station records management.
EMT records management
2.c. Response team records management
2.d. EMT shift logging (clocking in and out)
3. Subscriber management sub-system (SMS) Primary users: Managers
Direct and indirect subscriber recordsmanagement
4. Electronic patient care reporting sub-system(EPCR) Primary users: EMTs
Capture patient care data
Table 1 Selected user requirements
Interviews with Stakeholders
Interview with Mr. Tye Red, Chief Operating Officer, to understand details related to
handling of emergency calls and dispatching of response teams
Q. Please explain the concept of an emergency
A. There are many types of emergencies to which Rescue911responds. Typical
emergencies include: vehicle collisions, heart attacks, strokes, shootings, stabbings, child
birth,drownings, allergic reactions, choking, broken bones, and numerous other household
accidents and incidents.
Q. What are the responsibilities of operators when answering an emergency call?
A. Rescue911s call center operators are Emergency Medical Dispatchers that possess
special knowledge and skills. Dispatchers not only log calls and dispatch response teams,
they are also responsible for the medical aspects of dispatching, providing direction and prearrival instructions to callers. Through caller interrogation, dispatchers are able to evaluate the
severity of the injury or illness, allocate the call to a priority category, and ensure that they
dispatch an appropriate response configuration.
Q. How exactly is the priority category determined? And what role would you like the system
A. Operators are highly trained to determine the severity of an emergency and assign the
call to a priority category. This function is not required to be automated by the system. The
priority category of an emergency is determined by the dispatcher at the time of the call
based on information
provided by the caller. Criteria based dispatch guidelines provide a series of well-structured
questions that operators have been trained to ask of callers. The priority category, and the
estimated number of patients involved, determines the response configuration i.e. the
number and skills levels of response teams that need to be dispatched. The priority
1. Minor incident cases where treatment can be delayed. These are mostly minor single victim
/patient accidents requiring basic care levels.
2. Stable cases where single or multiple victims /patients are reported but all are
conscious and considered stable. Prompt but basic treatment levels are required.
3. Serious cases when a single or multiple victims /patients are reported and one or
more are unconscious or considered unstable due to possible injury to vital points.
Prompt and advanced treatment is desirable.
4. Critical trauma cases when a single or multiple victims / patients are reported and one or
more are unconscious, not breathing, or have lost a great deal of blood. Prompt and
advanced treatment is necessary for patient survival.
Prioritization is core to the effectiveness of the dispatch process to ensure that
appropriately qualified teams are dispatched to provide the appropriate level of care. The
dispatching operator needs to input the priority category of an emergency as well as the
number of response teams that are required. Operators also need to capture the address,
nearest landmark to the emergency, the phone number and name of the caller, and a brief
description of the emergency. Once these details of an emergency are captured, we
consider the emergency call as being in a logged state. The operator should then proceed
to dispatch a new response, or link the call to an existing emergency response.
Q. What do you mean by dispatching a response and linking the call?
A. An emergency call should result in what we term an emergency response. This is the
actual dispatching of one or more teams of particular skill that proceed to the emergency
location in a certain response mode (e.g. red lights and sirens versus routine
driving).Sometimes Rescue911 will receive more than one call for the same emergency
situation. Operators will determine if any new calls received are related to existing calls and
can then link the call to an existing emergency response. This will ensure that the operator
does not dispatch a response to an emergency which is already being dealt with. The
operator will inform the caller that Rescue911 is already aware of that emergency situation
and that a response team has already been dispatched to that scene. Obviously this is not a
faultless process and we have had situations before where two different emergencies have
occurred in close proximity. Operators have incorrectly assumed that callers have been
referring to the same emergency situation. Therefore, we would like an operator tube able to
refer the details of any emergency situation already recorded so that they can clearly
determine from the caller whether the emergency being reported is indeed a new one.
Q. Can you please explain more about the process of dispatching a response team?
A. Response teams are dispatched from one of 25 base stations. Response teams are
dispatched based on availability, proximity to the emergency location, and the response
teams grade. The new ERIS system does not need to determine which base station is
closest to the emergency. Instead, operators already have access to a sophisticated GIS/
GPS (geographic information system and global positioning system) that is used to map
emergency locations to base stations. When initiating a dispatch for a new emergency
response, wed like for the operator to simply be required to input into ERIS the base station
ID of the nearest base stations determined from the GIS / GPS system. Our GIS/GPS
system shows our base station locations, and emergency response flags. Operators use this
system to find base stations closest to reported emergency locations. Some of our very
experienced operators often know the different areas so well that they can recall by heart
the closest base station. Wed like for the new ERIS system tallow operators to use the base
station ID in order to begin the process of searching for an available response team. The
operator dispatches a response team by radioing the relevant base station Control to Base
Station AA.Response Team XXX Proceed to Location XXXXXX. Over.
Once a response team is dispatched, the operator waits for the response team to respond
over the radio system with Roger Control. Response Team XXX Proceeding to Location.
If no response is received within 15 seconds, the operator radios the team again. If no
response is received within further 10 seconds, the operator is required to dispatch another
team. The system should enforce this confirmation process i.e. the operator must confirm
that a response team has acknowledged the call and that they are preceding tithe scene.
Once confirmed, we consider the Emergency Call as having changed from a logged to
actioned state, and the system should record that a responding team has been
Q. What happens next?
A. The operator will radio a description of the emergency tithe responding team. The
operator will also request that responding team radio in to the control center upon arrival at
the scene. The response team will typically call in upon arrival with Response Team XXX
to Operator. Response Team XXX on Location. Respond. Over Any operator at the control
room can then respond Roger Response TeamXXX. This is important step in the process
as it allows us to know that a responding team is actually on-scene and the time of teams
Q. Does the process always run as smoothly as youve described it? Are there any
exceptions? (Question 4)
A. Yes, of course there will always be some exceptions. For example, if an operator is
attempting to dispatch a response team to an emergency but no teams are available from
an appropriate base station, the Emergency Call is flagged as waiting. Dispatch
supervisors are responsible for dealing
with all calls that are waiting. Usually, the supervisor will attempt to dispatch a team
currently in the field by radioing teams close to the scene and determining their availability.
Supervisors are able to do this by checking their AVL(automatic vehicle location) and
GIS/GPS systems to find teams in the field close to another emergency scene. Oral
system, lets us know where each responding team is at any point in time. If a supervisor is
able to dispatch a team in the field, then they should do that. If they cant, the supervisor
contacts another emergency services company e.g. County EMS.Once the other service
provider confirms they are attending to the call, the supervisor closes the call on our side.
Q. What is your expectation with regards to the integration of ERIS with the existing
GIS/GPS and the existing AVL system?
A. We dont want you to make any changes to the existing AVL or GIS / GPS system. Their
developers (Live TrackInc) will be responsible for integrating them with our new ERIS once
it is completed. They will ensure that the AVL system and the GIS/GPS system read data
from ERIS in order to update the maps. It is not within your brief to worry about those
systems. I only mentioned them so you could understand that those systems also play a
role in the overall process.
Interview with Ms Sue P. Phizer, Base Station Supervisor, to understand and clarify the
roles of EMTs and response teams
Q. Can you explain to us what an EMT does, and what is response team?
A. An EMT is a trained emergency medical professional. Within our company, EMTs can be
one of three EMT Grades. These are: basic EMT, paramedic, and critical care paramedic.
EMTs never work alone. They each belong to what we call a response team. Each
response team will have 3 to 4 EMTs. Each response team is assigned a team grade. The
teams grade is determined by the grades of themes that make up the team. The team will
be categorized as grade 1 (basic life support team), 2 (advanced life support team) or 3
(critical care team).
Q. Of what importance are these grades?
A. Grades come into play during the dispatch process. Im sure our COO explained that
process to you. I used to working the control room as a dispatch supervisor before I was
promoted to the base station supervisor, so I have a very good idea about how all the
pieces fit together. Let me explain: Grade 1, basic life support teams, can respond to
emergency priority categories 1 and 2. Grade 2, advanced life support teams, can respond
to categories 1, 2 and 3.Grade 3, critical care teams, can respond to categories 1, 2, 3and
4. Grade 1 teams ride in basic life support ambulances, while grade 2 and 3 teams ride in
advanced life support ambulances.Rescue911s priority dispatch rule is always to configure
response with a team whose grade meets the emergencys priority category rather than
exceeds it e.g. for a category 2 emergency, dispatch operators should first try dispatch
team with grade 1, if none are available then try a grade 2 team, if none available then
only try a grade 3 team. This is done to ensure that advanced and critical care response
teams are reserved for the most serious of emergency priorities.
Q. Can you please explain more about how the shifts work?
A. Response teams work on 1 of 3 shifts. There is a 12am to 8am shift, and 8am to 4pm
shift and a 4pm to 12am shift. When EMTs arrive for work, at their shift time, they need to
clock in. Response teams usually have three to four EMTs assigned. If a response team
has only 1 team member that has reported for duty on their allocated shift, then that
response team cannot be dispatched to any emergency scenes.
Q. It seems that some checks need to be performed when dispatching a team from a base
station such as yours to an emergency. Can you clarify?
A. Yes, the procedure from the control rooms point of view is to find from the nearest base
station, those response teams that are 1) on shift, 2) available for dispatch and 3) are
qualified to handle an emergency of the specified priority. But remember what I said earlier,
our business rule is to dispatch teams with just the right qualifications, so the operator must
dispatch a team with the lowest acceptable grade.
Q. Can you please go back to the concept of a shift so that I understand its implications for
A. A response team begins and ends a shift in what we call an invalid state. Once two or
more members of a response team have checked-in and reported for duty, the team then
becomes available. These on-shift teams will change state from available to away
multiple times in a single shift. When a response team gets dispatched to a scene and
acknowledges their acceptance of the dispatch to the operator, their state changes to
away. When the response team leaves a scene, the state changes back to available.
There is a further state called double-dispatch. If a team is in the away state and asked to
respond to an emergency by supervisor, their state will change from away to double
dispatch upon their acceptance of the supervisors order. Only control room supervisors
are able to double-dispatch teams in the away state. When an on-shift response team
becomes available, at the beginning of a shift, they are assigned a shift grade equal to
the value of their team grade. However, in the case of team whose default is critical care
(grade 3), that grade will only be assigned when at least one critical care paramedic has
reported for duty. If no members on duty are critical care paramedics then the team will be
assigned a shift grade of 2(advanced life support). Oh, I must clarify! It is the shift grade
rather than default team grade that
should be used when determining a teams eligibility to respond to an emergency. Please
Q. OK, so when deciding on which teams to dispatch, the operator should decide based on
the grade assigned to an on shift team, which might be different to their default team grade.
A. Yes. Youve got it.
Interview with Dr Warren Piece, Chief Medical Officer, to better understand emergency
Q. Can you please explain what happens at an emergency scene?
A. With pleasure. Insurance companies and doctors treating patients often require
Rescue911 to provide a report on the qualifications of EMTs responding to an emergency
call as well as the specific details of emergency care provided to patients at the scene. This
information together with information on their average response times may also be
requested by various national accreditation bodies when reviewing Rescue911s license to
operate as an emergency services provider. Therefore, at the scene of an emergency,
responding EMTs need to record information on emergency care provided including details
of procedures as well as medicines administered. Patient vital signs (heart rate and blood
pressure) also need to be recorded at the time the EMT leaves the scene or hands the
patient over to medical staff ate hospital. Details of the hospital or clinic to which a patient
was transported must also be recorded. Currently, we use field notebooks to record all
details about procedures and care given to patients. When we arrive or leave an
emergency scene, we always radio in to the operators at the call center to ensure that our
movements are recorded. By telling them were returning to base, they also know that
were available again to respond to other emergency calls.
Q. Im beginning to get a good picture. As you probably know, in version 1 of ERIS, all data
to be recorded by EMTs will be done at the base station. So your field note books will still
be necessary for now, and youd need to transcribe from those field note books to the ERIS
system upon arrival back at base.
A. Yes, we do understand. In fact I brought along a copy of the field note book to show you.
Q. But we are very excited about Version 2 of ERIS which will enhance the EPCR subsystem by rolling out handheld devices that will replace the field note books. Is there